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Methods are described for the determination of microgram or smaller quantities of nickel, cobalt and copper; these methods involve neutron activation of the samples in the Hanvell Pile, followed by radiochemical separation of the individual elements using carriers and, finally, comparison of the radioactivity due to these elements from the samples with that from known amounts of the elements that were irradiated simultaneously. The accuracy of the method has been checked for each element by analysing standard samples of steels, and the method can, in fact, be very useful for steel analysis when the levels of the three elements are lower than is convenient for existing methods.The results for terrestrial and oceanic rocks, marine sediments and meteorites are briefly examined with a view to the information they can give on the possibility of meteoritic origin of the nickel in marine sediments. Results are also quoted for the standard granite G1 and diabase W1, for some other rocks, commercial pure irons and, finally, for seaweeds.

It is shown that the oxygen present as impurity in beryllium metal can be determined by means of the micro-scale vacuum fusion apparatus, by using samples of 2 to 10 mg containing as little as 0.2 per cent. of oxygen, provided that a rigorous experimental procedure is followed. This consists essentially of exact temperature control and the use of a molten-platinum bath in the graphite crucible.The factors determining the optimum conditions are discussed fully and the difficulties involved in working with beryllium are stressed. The results obtained for different types of beryllium and beryllium '' spiked " with beryllium oxide are given, and thus the degree of accuracy possible with such very small samples is shown.Hydrogen can also be determined by this method.